Enveloped phaser

[Mark Hammer]

Based on your posted clip, I'm going to say that C23 needs to be bumped up to 2u2, and the Decay function should probably be something like a 4k7 in series with a 250k or 500k pot.  Trust me, you'll like the smoother transition.

[duck_arse]

hmmm. you got +9 at both ends of your 100R. R33//R34 gives your led driver gain, but taking the led//R1 to VB will then restrict its swing. and upset your bias voltage. take the R1 to supply, you might be able to increase R33. (with Mark's big value decay pot, R33 at 68k will load the cap and defeat the pot, to an extent.)

ahh, from your clip before last, I was wondering if your RC4558's driving leds were going lock-up reverse, possibly that tikking in yr prev clip. LM358's will be happy going down to ground, and won't swap output polarity when you least expect it.

[edit :] and I'm not sure you're supposed to sine-shape w/ a big cap there (130nF) - I thort that cap was just to take the peaks off a triangle.

[Kipper4]

Thanks Mark good call i've been playing with that.

Stephen I come clean. There were some copy paste errors included in the last schematic.

"I thort that cap was just to take the peaks off a triangle"
It made the wave much more user friendly so why not......

I'll take some nice scope piccy for you and send them to you.

Sorry guys

[Kipper4]

after another long night experimenting I think i'm back to where i was.
I did take R1 to supply with a 270k probably going to tweek that tonight.
That noise you can hear is probably down to my playing.

[Kipper4]

Sorry scrub that I had it all wrong on the breader.
Now I have  2u2 charge cap, 100K decay+1k stopper. 200k works too and Ive yet to experiment with that 200k value pot with regard to fade in and fade out phasing.
So thanks Mark and Stephen again.
I was wrong.

I'm settled on the enveloped depth.

I changed up some bias resistors You will see in the next scheme.
I think i'll end up with another dpdt switch for the mode switching. But hey so far I'm down to 3 pots and maybe two switchs.
Sw1 Vibe/Phaser
Sw2 fade in/Fade out
controls
Level for output
Decay
Lfo Rate

I changed the IC1 B led driver to a BJT buffer. Simply because i wanted less parts and a half of an op amp meant I'd probably try to find another use for the spare half and the bjt will do the job, take up less pcb space and parts.
So far I'm down to 4x dual op amps and a bjt.
Transistor input buffer and output amp might be on the cards too.

I took the time to try and calculate the "best" ldr for my application tonight and probably saved myself a lot of hours fannying on the breader.
I'll post a new drawing in the morning.
Thanks guys.

[Kipper4]

Daily update.
New schematic




https://youtu.be/fuIMBDgadbE

https://youtu.be/jHzUrvm8UR4

[amptramp]

Are you certain of your value for R28?  47K across the full 9 volts gives you 191.4 µA which would barely be noticeable LED output and this does not take into account the fact that there is a transistor, an op amp and a LED dropping voltage from that, so the 9 volts may be more like 6 volts.

[duck_arse]

R2 should be not needed. R1 and R5, if using single pole and two leds, can be reduced to a single 150k resistor, at the opamp output, switch common.

vact5B in parallel w/ R28, maybe?

two more videos? I'll never catch up. [seems a few percents were left, not long left now .....]

[Kipper4]

Are you certain of your value for R28?  47K across the full 9 volts gives you 191.4 µA which would barely be noticeable LED output and this does not take into account the fact that there is a transistor, an op amp and a LED dropping voltage from that, so the 9 volts may be more like 6 volts.

Yep thats the value I'm using. the voltage measured with the DMM is somewhere in the ball park of 4v5~7v
who'd have thought and its working.

@DA
I realised that I didnt need R2 also. I just pulled it from the breadboard to see, straight after I put it in and knew the lfo would provide enough, but thanks.

" if using single pole and two leds, can be reduced to a single 150k resistor"
in fact its a single led that i havent had time to sketch up the polarity switching.
and I changed R5 R1 to a single 470k.
I know..... amazing but it still works. and is very much in the county of aural results needed.
More on that in the vid. Watch it next month buddy, no rush.

Vact 5B and R28 // thats how i figuered to. Given my min depth Resistance of ~68K.
calculated by putting the depth pot (100k) back into the circuit. turn the pot until the horrible thumping disipated enough to make it pleasant, measure with the DMM.
Now that's science.......
Gl5528 specs say 10k-20k lux and 1M dark
It was supposed to be // with vact5B but and theres always a but.
The magic just didnt happen so i series it and boom "I'm back in the room".

The other end of the scale was that with 850k~1M dark depth (vact5B) the 4 leds from the phaser/vibe section simply dont light up enough to be heard.

I think this has to do with the 470k.
theres been some serious head scratching going on. I hope I dont have anymore funky breadboard junk going on so when i pcb it, it's not that at all. Aaaagh.

Thanks for the encouregment guys. Kudos to you all.
expect another vid......... Dont look DA.
Theres nothing in there thats not in this post. 'cept a flashing led and some close up elbows.

TTFN

[Kipper4]

https://youtu.be/kBgeVZfMlUg

[Kipper4]

Guys Please help I need confirmation or denial on if this will work for vactrol polarity switching.
With reference to ver7 the Vact 5 B led hanging off of IC7 A output.
(the two leds are one of the same, NOY two seperate ones)
Thanks

[PRR]

Switch is 3x3 lugs. How do we (or you) know which way it goes?

However tossing it in my head, I'm not seeing happiness.

Or a need for a 3P switch. (2P would eliminate the ambiguity of switch orientation.)

[PRR]

http://oi65.tinypic.com/6o24ip.jpg

[Kipper4]

Thanks Paul that's brilliant.
It's a shame I didn't see it like that.
That should work a treat.
My drawing was in fact a 3pdt. I should have made it a lot clearer.
I was referencing the numbering found in an Internet image like the 3pdt here top of the page.

http://effectslayouts.blogspot.co.uk/p/general-layout-notes.html

[duck_arse]

I'm back, and caught up. it sounds like someone swelling a church organ, maybe. or some weird auto-wah.

carry on.

[midwayfair]

This sounds good.

Small suggestion: You can make the design a lot less expensively by using discrete LDRs instead of vactrols. You just crowd them around the LED like a univibe bulb. Like this:



If you plan on putting a bunch of LEDs in parallel, you may need to match them or some of them can behave strangely. In this case, though, you have enough redundancy from the extra stages that it's easier to just use the single LED.

You may also want to consider a simple input buffer. A JFET would only be a couple parts. The input impedance is <200K right now. I can some loading on the guitar in the video and it's making it sound a little dark.

[Kipper4]

Thanks Jon.
The number of seperate vactrols was giving me a headache at the layout stage. So the discrete idea is just what I needed.
I'm going with it and intend to use an 8 pin dip IC socket to mount it on. Single led throught the hole in the middle of the socket.

Question Why do they call it discrete when its anything but in appearance?


It is loading the guitar. I've drawn up a possible solution with your idea for a jfet buffer (AMZ plageurised)

I tried it with the input buffer and it went well earlier, then i tried it with a bjt amp on the output. Hoping to eliminate a further dual op amp. That didnt go so well I'm getting a lot of unwanted noise. Hence why I left IC2A and IC1 B (dual TL072)ver11 below

Please forgive the odd parts numbering it needs cleaning up. Once I am sure it's what is needed.

I can't figure out if i need to AC couple the buffer to the IC. Do I need C5?
Thanks guys
Rich

[Kipper4]

Ooops quicky fix.
Yes sir I do need C5 or it jams the IC2-A buffer at the power rail (8+v)

[duck_arse]

kipper, measure the voltage on both sides of the C5. if diff then yes, else same equals no. and R27 sets the input impedance of that stage, so if it sucks, increase it. mind, I suck at opamps, so this might be bad advice.

have you tried running R9 and vact leds right off the opamp, and delete Q1 and R3? conversly, you might be able to use them to drive the leds, but shift the vol-sweeping ldr to the Q1 base, with another resistor to form a voltage divider. like der tremolo you was playing wit.

[Kipper4]

Double post removed see over page.